Field of the Invention
The present invention relates to a sheet conveying apparatus that performs skew correction of a sheet, and to an image forming apparatus including the same.
Description of the Related Art
Recently, image quality is desired to be improved in image forming apparatuses such as copying machines, printers, and facsimiles. For this reason, improvement against image position deviation due to skew feeding or turning (sector) in sheet conveyance is particularly required.
For example, a leading edge of a sheet fed out from a sheet feeding apparatus is hit against a pair of registration rollers whose rotation has been stopped, and in that state, a pair of pre-registration rollers are driven to further feed the sheet to form a loop in order to correct the skew feeding of the sheet is generally known.
However, in this conventional configuration, there is a risk that the sheet whose skew feeding has been corrected by the pair of registration rollers and the pair of pre-registration rollers may be stressed by the pair of registration rollers and the pair of pre-registration rollers, and wrinkles or the like may occur. In order to prevent this, a configuration has been proposed in which the pair of pre-registration rollers is separated so as to release the nipping on the sheet by the pair of pre-registration rollers after correcting the skew feeding of the sheet as described above (Japanese Patent Laid-Open No. 11-79474).
However, depending on the configuration of the conveyance path of the sheet, in the case where the pair of pre-registration rollers is separated immediately after the skew correction, the influence of the conveyance resistance due to the slide friction between the sheet and the conveyance guide for guiding the sheet may become large. In this case, there is a possibility to cause skew feeding or turning of the sheet due to the conveyance resistance so as to worsen the image position deviation or to deteriorate the sheet conveyance to cause wrinkles, scratches, sheet jams, and the like.